The invention generally relates to an improvement in close-off valves in suction lines of the kind comprising a valve housing in which a spring-loaded piston is movably mounted. The rod of the piston supports a valve disc which is arranged to move into a position in engagement with a valve seat for the purpose of shutting-off a suction line.
The purpose of the invention is to provide a close-off valve, which is arranged, while shutting-off a flow of a medium, such as a hydraulic fluid from the source to the consumer, e.g. a hydraulic pump, to allow a small flow of the hydraulic fluid, thus effecting lubrication and to some extent cooling of the hydraulic pump when the latter is running idle, that is when the valve disc is in its position abutting against its valve seat to close off the main passageway through the valve.
More precisely, the invention relates to an improved close-off valve for suction pipes in hydraulic pumps of the kind comprising a hydraulic piston system which is controlled by a tilting disc in order to generate a flow of a hydraulic medium in the main passageway. The tilting disc abuts against a thrust bearing and in the pump housing is provided also a laterally directed passageway allowing passage-through of a small amount of oil which is sufficient to lubricate and cool the pump. The valve disc which is supported by the piston rod of the spring-loaded piston, which is movably mounted in the valve housing, is arranged to be controlled by a solenoid valve and to be moved into abutment against a valve seat for the purpose of shutting off the connection means to the main passageway of the pump.